How would you plot the gradient vector field of f(x,y)=x^2-3*x*y+y-y^2 on the domain [-4,4]*[-4,4] in Mathematica 7?
I know the function is "VectorPlot" (h t t p : / / g o o . g l / p c S f), but I don't know how to isolate the x and y inputs because of the -3*x*y term in the function.